Pump loading and unloading mechanism



Mar. 3, 1925. 1,528,547

J. E. HoLvEcK PUMP LOADING AND UNLOADING MECHANISM Filed June l1, 1924 FII-5.2. Z

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Patented Mar. 3,1925.

UNITED STATES PATENT OFFICE.

' JOSEPH HO'LVECK, OF PITTSBURGH, PENNSYLVANIA,

rum LOADING .um UNLoAnINe uncnamsn Application illefvl June 11,

. loading pumps used in translating fluid from one po'int to a point of higher pressure.

In -the use of high pressure pumps such, for example, as those used for pumping iuid into ressure accumulatore, it is common practlce to drive the pum s, which are usually of the multiple cylin er type, by. means of electric motors connected directly to the pumps. The motors are driven continuously and when the need for operating the pump ceases, instead .of Dstop ing'the motor it is customary to unload t e pump by holding the suction valve thereof open until operation of the pump is again Vrequired.

An object of 'this invention is to provide an improved means for automatically loading and unloading a pump in such manner that the torque on the pump crank shaft is increased gradually from zero to maximum and vice versa.

A further object is to provide a device of the type set forth which is so controlled as to load or unload any given cylinder of the pump only on the suction stroke.

A still further object sto rovide a device of the type set forth whicican be used in connection with any single or multiple cylinder pump and which is simple and cheap to manufacture, rugged in construction and positiveand reliable in operation.

These and other objects which will be apparent to those skilled in this particular ait are accomplished by means of this invention, one embodiment of' which is shown, for the purposes of illustration, in the accompanying drawings, in which Figure l is a side elevationof a multiple cylinder pump provided with this invention, only so much of the pump structure being shown as is necessary to a clear understadigpthe present invention, Fig. 2 is anend elevation of the' structure shown in Fig. 1, parts beingshownin section along the line 2--2 of Fig. 1 and Figs.'3 and 4 are diagram- 1924. serial 1ro. 719,370.

matic views illustrating the relative positions ofthe crank arms and the solenoid controlling switches on the pump .crank shaft.

Devices for unloading pumps, as heretov fore constructed, have operated in such a manner as to unload the various cylinders of a multiple cylinder pumpin a particular sequence only.` vIn a three cylinder pump, -for example, the unloading always started with cylinder number one, then number two andthen number three. This necessarily increased the time for unloading as it prevented the unloading means -forl -cylinders number two and three from operating until that for cylinder number one had functioned.

The present invention contemplates an unloading device which, when applied to multiple cylinder pumps will operate instantly beginning with whatever c linder is at the moment on a suction strolie. It is not necessary for the device to follow any particular sequence or to wait for any particular cylinder to unload first.

The illustrated 'embodiment of this invention is shown as applied to amultiple cylinder ump 5 having the usual crank shaft 6 driven by a large gear wheel-7 which also acts as a-iy wheel. The gear wheel 7 meshes with and is driven by a spur gear 8 mounted on the shaft of an electric motor 9. Each cylinder 10 of the pump, see Fig. 2, has the usual reciprocating piston or plunger 11. Each pressurechamber 12 has the usual outlet valve 13 which permits the passage of fluid to a storage reservoir or` accumulator on each pressure stroke of the plunger 11. `An inlet o r suction valve 14 1s provided in the pressure chamber for permitting the passage of Huid thereto on each suction 'stroke of the plunger, all as is well lmown in this art.

The suction valve 14 has the 'usual valve stem 14. Below the valve stem a lifting stem orftappet 15 extends downwardly below the pumpv casing and engages one arm .of a horizontal lever 16 which ispivoted at ists center to a bracket/17 secured to the bottom ofthe pum casing. The other arm of the lever 16 is plvoted Yto a link 18 which in turn issecured to the core .of a solenoid 20 mounted on the` pump casing directl above the outer end ofA the lever 16.` X helical spring 21'surrounds the link 18v and is compressed between the base of the solenoid and a spring block 22 which is inounted on the lower end of the link 18.

In order to unload the pump it is only necessary to break the circuit of the solenoid. This permits the spring 21 to eX- pand and oscillate the lever 16 so as' to raise the lifting stem 15 and hold the suc-v tion valve 14 raised from its seat. The str. gth of the spring 21 is such that if the solenoid is released while the plunger 11 is on a pressure stroke the pressure thus caused will hold valve' 14 closed so that the spring 21 will expand and unload the valve 14 only when the plunger is on a suction stroke. current is passed through the solenoid, thereby raising the link 18 and through the agency of the lever 16 lowering the lifting stem 15 so as to permitl the valve 14 to seat at the end of the suction stroke or 'at the beginning of discharge stroke.

rI`he solenoids are controlled by means of a switch 23 in the main circuit. This switch may be a push-button, a float-switch or any desired type of circuitbreaker and it may be automatically controlled by the position of the accumulator or pressure of a pneumatic tank which the pump 5 feeds. On closing the switch 23 each solenoid will be actuated so as to load each cylinder of the pump. In order to prevent jar and strain and to increase the torque on the pump crank shaft gradually from zero to maximum each solenoid is automatically controlled so as to be energized only during the suction stroke of each plunger by the following mechanism: A drum 24 of non-conducting material is mounted on an extension ofthe crank shaft 6 so as to rotate therewith. NThe drum 24'has a circular contact 25 mounted thereon which is electrically connected to semi-circular contacts 26, 27 and 28. A bracket 29 is mounted on the pump fra-me directly beneath the drum 24 and is provided with brushes 31, 32, and 34 which are adapted to make an electrical contact with the contacts 25, 26, 27 and 28. respectively.` The brush 31 is connected in the main circuit. The brushes 32, 33 and 34 are each connected in the circuit of a single solenoid. The contacts 26, 27 and 2S are so positioned on the pump shaft in relation to the crank arms that, after closing the switch 23, each solenoid will be energized only when its associated plunger 11 is on a suction stroke. Each solenoid is provided with a contact 35 which is mounted on the core thereof and which is adapted to operate a relay switch 36 mounted on the top of each solenoid.

When the switch 23 is closed, current passes through"the brush 31, contact 25 and thence through the contacts 26, 27 and 28 and brushes 32, 33 and 34 so as to energize each solenoid and remove the interference When it is desired to load the pump under each, valve 14 whenf the associated plunger 11 is-on its suction stroke, thereby allowing each cylinder to load only at the end of its suction or beginning of its discharge stroke. crgized each contact 35, which is mounted on the core, is raised so as to close the relay switch 36 thus permitting current to pass directly through the solenoid and maintain it energized irrespective of the contacts on the drum 24. To unload the pump, switch 23 is opened, releasing each solenoid 2O and permitting the spring 21 to expand so as to raise the lifting stem 15 and raise the valve 14, such operation, however, occurring only on a suction stroke, as above described.

With this arrangement the unloading starts with the cylinderon the suction stroke and each successive cylinder is uuloaded as its plunger competes fthe suction stroke. and it is not necessary to load or unload the cylinders in any particular sequence. As shown in Figs. 3 and 4, the brushes 32, 33 and 34 control the operation of the solenoids on the cylinders whose plungers are driven by the crank arms 3S. 39 and 40, respectively. The contacts 26. 27 and 28 are so placed that current flows through the Vbrushes to the solenoids only when the respective crank arms and plungers are on a suction stroke. This resultsI in a `gradual increase of the torque from zero to maximum and preven-ts the jar and strain which results from loading a cylinder when the plunger is on a pressure stroke.

While `I have described a preferred embodiment of the prese-nt invention I do not wish to be limited to the specific details thereof but what I claim as new and desire rto secure by Letters Patent is:

1. The combination with a pump of mechanism for loading and unloading said pump including magnetic. means and a control dcvice operated in synchronism with the rotation of the pump shaft for permitting said pump to load only at the beginning of a discharge stroke.

2. The combination with a pump, of mechanism for loading and unloading said pump including an electro-magnet, and controlling means operated in synchronism with the rotation of the pump shaft for permitting said pump to load Ionly at the heginningof a discharge stroke.

3. The ycombination with a pump of mechanism for loading and unloading said pump including a solenoid, and a control switch in the circuit of said solenoid operated in synchronism with the rotation of said pump shaft for permitting said pump to load only at the beginning of a discharge stroke.

4. The combination with a pump of means for unloading said pumip, magnetic means for loading said pump and means actu- As each solenoid is enated by said pumpfor permitting said pump to load only at the beginningof a discharge stroke.

5. The combination with a pump of means for unloading said pump, magnetic means for\loading said pump and means actuated by a moving part of said pump for permittingsaid pump to load only at the beginning of a discharge stroke.

v for unloading said pump, a solenoid adapted A tion stroke.

to be actuated so as to prevent the operation of said means and permit said pump to load and means for preventing the actuation of said solenoid until said pump is on asue- 9. The combination with a pump of resilientmeans for unloading said pump, a solenoid adapted 'to be actuated so as to prevent the operation of said means and permit said pump to load and a pumpcontrolled switch for preventing the actuation of said solenoid until said pump is on a suction stroke.

10. Thecombination with a pump of means for unloading said pump, a solenoid adapted to be actuated so as to prevent the operation of said means and permit said pump to load, a pump controlled switch for preventing the actuation of said solenoid until said pump is on a suction stroke 'and a relay switch for maintaining said solenoid in pump loading position.

11. The combination with a pump of means for unloading said pump, a solenoid adapte-d to be actuated so as to prevent the operation of said unloading means and permit said pump to load, a. pump controlled switch for preventing 'the actuation of said solenoid until said pump is on a suction stroke, a relay switch for maintaining said solenoid in pump loading position and means for decnergizing said solenoid so as to unload said pump.

12. The` combination with a pump of means for unloading said pump, a solenoid adapted to be actuated so as to prevent the operation of said unloading means and permit said pump to load, a pump controlled switch for preventing the actuation of said solenoid until said pump is on a suction stroke, a solenoid operated relay switch for maintaining said solenoid in pump loading position and means for deenergizing said solenoid so as to unload said pump.

13. The combination with a pump of means for unloading said pump, a solenoid adapted to be actuated so as to prevent the operation of said means and permit said .pump to load, a pump controlled switch for preventing the actuation of said solenoid until said pump is on a suction stroke and a solenoid operated relay switch for maintaining said solenoid in pump loading position. 14. 'lhe combination in a pump of a suction valve, a lifting stem for raising said valve, a lever engaging said lifting stem, lyielding means adapted to operate said lever so as to raisesaid -valve and unload said pump and means-adapted to be operated in synchronism with the rotation of the pump shaft for rendering said yielding means inoperative.

A15. The combination with a pump of a suction valve, a lifting'stemj for raising said valve, a lever engaging said lifting stem, yielding means adapted to operate said lever so as to raise said valve and unload said pump and electro-magnetic means adapted `to be operated in synchronism with the rotation of the. pump shaft so as to render said yielding means inoperative.

In testimony whereof, I have hereunto subscribed my name this 7th day of June, 1924.

JOSEPH E. nommen. 

